Recently, recycling of products in which fiber-reinforced plastics (FRPs) are used have been demanded, and the recycling techniques include crushing and thermal decomposition. Patent Document 1 (JP-A-4-22477) discloses dismantlement of molded coils of epoxy resin, in which the coils are heated, thermally decomposed and hydrolyzed at high temperature with water or aqueous alkaline solution.
Patent Document 2 (JP-A-2001-172426) discloses treatment in which hardened epoxy resins are decomposed and dissolved. Non-patent Document 1 describes recycling of common FRPs.    (Patent Document 1) JP-A-4-22477    (Patent Document 2) JP-A-2001-172426    (Non-patent Document 1) Hitachi Chemical Technical Report No. 42 (2004-1).